Credit card: China UnionPay card can be directly swiped by Koreans.
All major UnionPay cards in China can be used, but it is best for UnionPay cards to have my name on the front (the signature on the back is invalid). If there is no name on the front, you need to show proof at the bank or pull the statement (the official seal of the bank is required).
Remittance: I need to use my passport to open an account in a local bank in Korea, then remit money to my account in Korea through my account in Hong Kong or other overseas countries, and then use the money in my account in Korea to buy real estate.
Cash: If customers bring cash (non-Korean won) into the country, they must make a customs declaration when entering the country (Korean entry customs will not ask about the source of the money, but only tell the customs that they are coming to invest and ask the customs to show the investment certificate).
Loan: You can apply for a loan at a local bank for the part exceeding $500,000.
It should be noted that buying a house and sending a green card is a kind of welfare used by the government to attract foreign investment, which has little to do with developers. Therefore, if you don't need a green card, you can pay it how you want, but if you need to go through the immigration formalities for Jeju Island real estate investment, you must show proof of foreign investment. Only when you can fully prove that the funds are invested in South Korea from outside South Korea will the Korean government grant investors a green card in South Korea.
I hope I can help you.